This invention relates to a machine for cutting, conditioning and windrowing crop material such as grasses and legumes and more particularly to an improved conditioning means for such a machine in which a generally transverse cutter bar delivers cut material rearwardly to an adjacent impeller rotor parallel to the cutter bar for conditioning and discharge into a windrow.
Typically, such machines are provided with a hood over the rotor, the forward part conforming fairly closely to a forward and upper quadrant of the rotor periphery and creating a confined conveying channel or conditioning zone through which crop material is carried by the rotor before being discharged rearwardly into a crop deflecting and windrow forming portion of the hood. The configuration and disposition of the hood portion forming the conveying channel and conditioning zone have important effects on power consumption and material flow control as well as on the intensity of crop treatment or conditioning and, although operating and crop conditions vary widely, some machines offer no provision for adjustment in this area.
The known attempts to offer some adjustment suffer from some limitations and disadvantages. For example, U.S. Pat. No. 3,092,946, Matthews, discloses a machine in which both cutting and conditioning are done by a rotor and in which a forward portion of a hood is hinged directly to a rearward portion of the hood by a fixed hinge to provide adjustment of radial clearance at the crop entry to the conveying channel. Independent adjustment of crop entry height is achieved through a completely separate transverse push bar mounted independently ahead of and below the adjustable hood portion. German Pat. No. 2,147,375 assigned to Bucher-Guyer AG discloses an impeller mower-conditioner in which only the lower or leading edge of an otherwise fixed hood is adjustable providing a range of adjustment for height of entry into the conveying channel and for the width of the entry to the channel itself. In both cases the adjustment means provided principally affect the conveying channel entry and require two separate adjustment operations. Some of the combinations of height and radial clearance setting provided result in undesirable, potentially power consuming and flow deflecting discontinuities on the inner surfaces of the conveying channel adjacent its entry.
Another approach to providing control of conditioning intensity is disclosed in U.S. Pat. No. 3,699,755, Bucher-Guyer, where a comb-like impedance may be adjustably intruded into the conveying channel. But here again the attempt is to control the function of a control surface of substantial circumferential extent by a quite localized modification.